Semiconductor package and system

ABSTRACT

Even when only one of semiconductor packages mounted by carrying out infrared reflow is defective, it is required to carry out infrared reflow again to dismount this defective semiconductor package from a mounting board. At this time, stress of heat is also applied to the other non-defective semiconductor packages. For this reason, if infrared reflow is carried out beyond a number of times of infrared reflow specified for non-defective semiconductor packages, the operation of each non-defective semiconductor package cannot be assured. In this case, it is inevitable to discard the semiconductor packages together with the mounting board. To solve this problem, a magnetic material is passed through a hole penetrating a protection member and a package board and the relevant semiconductor package is fixed over a mounting board by this magnetic material. To supply power to the semiconductor package, electromagnetic induction by coils provided in the package board and the mounting board is used.

CROSS-REFERENCE TO RELATED APPLICATIONS

The disclosure of Japanese Patent Application No. 2009-257318 filed onNov. 10, 2009 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention relates to semiconductor packages and systems andin particular to a semiconductor package and a system wherein necessityfor mounting to a mounting board by solder is obviated.

There are conventionally known technologies for mounting a ball gridarray package 10 (hereafter, abbreviated as BGA 10) over a mountingboard 11 as illustrated in FIG. 1. (Refer to Patent Document 1.) In thetechnology disclosed in Patent Document 1, BGA 10 is comprised of apackage board 13, a semiconductor element 14, a protection member 15,and a solder ball 16. The package board 13 is comprised of a core basematerial 17 composed of glass cloth, resin, or the like and solderresist 18 covering the upper surface and lower surface of the core basematerial 17 in the drawing.

An opening is provided in the solder resist 18 covering the uppersurface of the core base material 17 and a bonding pad formed over thecore base material 17 is exposed from this opening. This bonding pad iscoupled to a wiring pattern provided in the upper surface of the corebase material 17 and this wiring pattern is coupled to a via hole soprovided that it penetrates the core base material 17.

The semiconductor element 14 and this bonding pad are coupled togetherthrough a bonding wire 21 and as a result, the semiconductor element 14and the package board 13 are electrically coupled together. In the lowersurface of the core base material 17, a substantially oval ball land isformed. This ball land is coupled with the above-mentioned via hole soformed that it penetrates the core base material 17 and is electricallycoupled to the semiconductor element 14 through the following: thewiring pattern provided in the upper surface of the core base material17, a bonding pad, and a bonding wire 21 bonded with this bonding pad.This ball land is exposed from an opening provided in the solder resist18 covering the lower surface of the core base material 17. Before theBGA 10 is mounted to the mounting board 11, the solder ball 16 is placedover a ball land by a ball placer, not shown. The placed solder ball 16is joined to the ball land by IR reflow processing or the like and thejoined solder ball 16 makes an external connection terminal electricallycoupled with the semiconductor element 14. The protection member 15protects the semiconductor element 14 and the bonding wire 21.

Similarly with the package board 13, the mounting board 11 is comprisedof a core base material 25 and solder resist 26 covering the uppersurface and lower surface thereof in the drawing. In the upper surfaceof the core base material 25, there is formed an area (mounting area)where the BGA 10 is mounted. In this mounting area, there is formed asubstantially oval junction land corresponding to a solder ball 16joined to a ball land of the BGA 10. This junction land is exposed froman opening formed in the solder resist 26 covering the upper surface ofthe mounting board 11. The junction land is electrically coupled withsome other mounted electronic component or a power supply through awiring pattern formed in the upper surface of the mounting board 11.When the BGA 10 is mounted to the mounting board 11, the solder balls 16of the BGA 10 are abutted against the above-mentioned junction landsprovided in the mounting board 11. Subsequently, the BGA 10 and themounting board 11 are subjected to IR reflow and as a result, the solderballs 16 are joined to the junction lands of the mounting board 11 andmounting of the BGA 10 to the mounting board 11 is completed.

Patent Document 2 discloses a technology for fixing a semiconductorpackage over a circuit board. In this technology, the semiconductorpackage is fixed over the circuit board by: passing a bolt through aninsertion hole in the semiconductor package and inserting the bolt intoa communication hole in the circuit board; and screwing a nut onto thetip of the bolt that penetrates the circuit board and is protrudedtherefrom.

Patent Document 3 discloses a non-contact power supply system usingelectromagnetic induction based on a printed coil.

Patent Document 4 discloses that in an electrical apparatus providedwith a primary coil and a secondary coil, power is transmitted to thesecondary coil in a non-contact manner by supplying a current to theprimary coil.

Non-patent Document 1 discloses a technology related to measurement of2.4 GHz RF signal quality. Non-patent Document 2 discloses a technologyrelated to communication through an antenna using a coil.

-   [Patent Document 1] Japanese Unexamined Patent Publication No.    2007-12690-   [Patent Document 2] Japanese Unexamined Patent Publication No. Hei    07(1995)-161865-   [Patent Document 3] Japanese Unexamined Patent Publication No.    2007-157985-   [Patent Document 4] Japanese Unexamined Patent Publication No.    2004-064851-   [Non-patent Document 1] Koichi Nose et al., “A 0.016 mm², 2.4 GHz RF    signal Quality Measurement Macro for RF Test and Diagnosis” IEEE    JOURNAL OF SOLID-STATE CIRCUITS, VOL. 43, NO. 4 April 2008, pp    1038-1046-   [Non-patent Document 2] Kiichi Niitsu et al., “An inductive-Coupling    Link for 3D Integration of 90 nm CMOS Processor and a 65 nm CMOS    SRAM” ISSCC Dig. Tech. Papers, pp. 480-482, February 2009.

SUMMARY

The present inventors founds that the technology disclosed in PatentDocument 1 involves the following problems. As mentioned above, the BGA10 in FIG. 1 is mounted to the mounting board 11 using solder balls 16.When a semiconductor package (equivalent to the BGA 10 in FIG. 1)including a semiconductor element (pellet) is mounted to a mountingboard by solder, the following takes place: it is difficult to dismounta once mounted semiconductor package and mount a different non-defectivesemiconductor package to the identical mounting board again. The reasonfor this is as follows. Usually, semiconductor packages should bescreened through quality inspection or the like and non-defectivesshould be shipped. Nevertheless, a defective may be produced amongmounted semiconductor packages because of stress applied duringmounting, deterioration with age, or the like. Therefore, even in caseswhere one semiconductor package is defective, for example, when multiplesemiconductor packages are mounted to a mounting board to build asystem, it used to be inevitable to take the following measure: it usedto be inevitable to discard the value-added mounting board mounted withnon-defective semiconductor packages in its entirety. The reason forthis is as follows:

To mount semiconductor packages using solder balls, it is required tocarry out infrared reflow (hereafter, referred to as IR reflow) asdescribed in Patent Document 1. In this IR reflow, a mounting boarditself mounted with the semiconductor packages is placed in a furnacefor IR reflow and heat is applied to the entire semiconductor packagesmounted over the mounting board. Therefore, stress of heat arising fromthe IR reflow is applied to all the semiconductor packages mounted overthe mounting board.

The maximum number of times of IR reflow that can be carried out onsemiconductor packages is prescribed beforehand. In case of NECElectronics Corporation, for example, it is prescribed that IR reflow inwhich heat at 260 degrees may be carried out up to twice onsemiconductor packages specified as IR60-103-2. When a system is builtover a mounting board at the corporation, IR reflow is carried out tomount multiple semiconductor packages. Even if one semiconductor packagethereafter becomes defective and this semiconductor package is found tobe a defective, IR reflow must be carried out again to dismount thisdefective semiconductor package. To carry out IR reflow, as mentionedabove, the mounting board itself must be placed in a furnace. As aresult, stress of heat arising from the IR reflow is also applied to theother non-defective semiconductor packages. To replace the defectivesemiconductor package with a non-defective semiconductor package andmount it over the mounting board, IR reflow must be carried out onceagain. That is, even when it is desired to dismount only a defectivesemiconductor package mounted over a mounting board and replace it witha non-defective semiconductor package, stress of heat arising from IRreflow is also applied to non-defective semiconductor packages.Therefore, IR reflow can be carried out beyond the number of time of IRreflow prescribed for non-defective semiconductor packages. With respectto non-defective semiconductor packages, in this case, it cannot beassured that those semiconductor packages are non-defective.

In this case, with respect to semiconductor packages that are mountedover a mounting board and should be otherwise non-defective, it cannotbe assured that they are non-defective. Eventually, therefore, all ofthem must be discarded together with the mounting board.

Conventional technologies pose a technical problem to be solved when asemiconductor package is mounted to a mounting board by solder. That is,it is impossible to dismount the once mounted semiconductor package andmount a different semiconductor package over the identical mountingboard. Therefore, if a defective semiconductor package is produced inthe processes of manufacturing and mounting semiconductor packages, itresults in increase in cost.

A semiconductor package according to the invention includes: a packageboard including a coil that supplies power based on an induced currentpassed in response to change in magnetic flux; a pellet provided overthe package board and including a circuit that operates based on powersupplied from the coil; a protection member covering the package boardand protecting at least the pellet; a first hole penetrating theprotection member; and a second hole surrounded with a wiring formingthe coil and penetrating the package board.

A semiconductor manufacturer who manufactures and sells semiconductorpackages ships semiconductor packages having at least theabove-mentioned configuration as a product. A customer supplied withthese semiconductor packages from the semiconductor manufacturer carriesout the following processing to mount semiconductor packages over amounting board: a fixing member, for example, a magnetic material ispassed through the first hole and the second hole in each semiconductorpackage. The mounting board over which the semiconductor packages aremounted is separately provided with a coil. This mounting board isprovided with a hole (here, tentatively referred to as third hole)surrounded with a wiring forming this coil and penetrating the mountingboard. Therefore, the customer supplied with the above-mentionedsemiconductor packages passes the fixing member passed through the firstand second holes provided in each semiconductor package also through thethird hole and thereby fixes the semiconductor package over the mountingboard. As an example, a configuration in which the following measure istaken is possible: the fixing member is passed through the third hole aswell as the first and second holes and passed along side surfaces of themounting board and each semiconductor package to form one closed loop;and the semiconductor package is thereby fixed over the mounting board.To configure this magnetic material in a closed loop, joints can bewelded by heat. As another example, the magnetic material may be formedin an open loop in which part of the loop is discontinuous, not in acomplete closed loop and each semiconductor package is thereby fixedover the mounting board. When the magnetic material is formed in an openloop, welding by heat is unnecessary and each semiconductor package isfixed over the mounting board by hooking it on the mounting board by theopen-looped magnetic material. As a result, it is unnecessary for thecustomer to carry out IR reflow to mount the semiconductor packages overthe mounting board.

To dismount one of the thus mounted semiconductor packages, IR reflow isunnecessary. That is, it is unnecessary to place them in a furnacetogether with the mounting board to apply heat to the entiresemiconductor packages mounted over the mounting board. Specifically,the magnetic material fixing a semiconductor package to be dismountedover the mounting board only has to be mechanically cut. Therefore, itis unnecessary to apply heat to the semiconductor package that must bedismounted from the mounting board. In case of semiconductor packagesmounted over a mounting board using a magnetic material configured in anopen loop, welding by heat is not originally carried out. To dismountsuch a semiconductor package from the mounting board, therefore, thesemiconductor package can be dismounted from the mounting board bychanging the shape of the magnetic material by physical force.Consequently, it is possible to dismount a defective semiconductorpackage among multiple semiconductor packages mounted over a mountingboard and instead mount a non-defective semiconductor package over thismounting board. As a result, when one of semiconductor packages mountedover a mounting board is defective, it is unnecessary to discard all ofthem together with the mounting board unlike conventional technologies.

When a semiconductor package is mounted over a mounting board asmentioned above, there is a concern about power supply to thesemiconductor package. A circuit included in the semiconductor packagemounted without use of solder balls is operated by supplying power fromthe mounting board to the semiconductor package by the principledescribed below:

The mounting board is provided with a power supply IC that suppliesalternating-current voltage whose voltage value varies based on thefrequency. When alternating-current voltage outputted from the powersupply IC is applied to a coil provided in the mounting board, thecurrent passed through this coil is also varied. In response tovariation in the current passed through the coil provided in themounting board, the magnetic flux produced by this coil also changes.Based on this change in magnetic flux, an induced current arising fromthe phenomenon of electromagnetic induction is passed through the coilincluded in the package board. In consideration of that, for example,recent circuits operate on direct-current voltage, power is supplied toa circuit included in the pellet of a semiconductor package byrectifying this induced current and the circuit operates. When thefixing member used to fix each semiconductor package over the mountingboard is magnetic material, the magnetic material contributes toreduction of the amount of flux leakage and supply of a sufficientamount of power from the mounting board to each semiconductor package.

According to the foregoing, it is possible to dismount a defectivesemiconductor package among multiple semiconductor packages mounted overa mounting board; and instead mount a non-defective semiconductorpackage over this mounting board. This makes it possible to solve thefollowing problem associated with conventional technologies: it isdifficult to dismount a mounted semiconductor package and mount adifferent non-defective semiconductor package over the identicalmounting board again.

According to the invention, it is possible to mechanically mount asemiconductor package over a mounting board without use of heat.Therefore, even though a defective semiconductor package is produced inproduct development, increase in cost can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing illustrating the configuration of a semiconductorpackage according to a conventional technology;

FIG. 2 is a drawing illustrating the configuration of a system in afirst embodiment;

FIG. 3 is a drawing illustrating a modification to the first embodiment;

FIG. 4 is a drawing illustrating a modification to the first embodiment;

FIG. 5 is a drawing illustrating a modification to the first embodiment;

FIG. 6 is a drawing illustrating a modification to the first embodiment;

FIG. 7 is a drawing illustrating the configuration of a system in asecond embodiment;

FIG. 8 is a drawing illustrating the configuration of a system in athird embodiment; and

FIG. 9 is a drawing illustrating a system in the third embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereafter, description will be given to embodiments of the inventiondisclosed in this specification with reference to the drawings. Thescope of right of the invention is determined by the description in“What is claimed is” and should not be construed in a limited way by thefollowing description of the embodiments.

First Embodiment

FIG. 2 illustrates a system 200 in the first embodiment. The system 200is, for example, a system developed by an assembled product manufacturersupplied with semiconductor packages from a semiconductor manufacturer.The system 200 includes a mounting board 201. The mounting board 201 isa board used by the assembled product manufacturer to mountsemiconductor packages supplied from the semiconductor manufacturer. Themounting board 201 includes a power supply IC, typified by a battery orthe like, that converts externally supplied power into a predeterminedvoltage and outputs it. The mounting board 201 in this embodimentincludes a power supply IC that outputs alternating-current voltagebased on inputted voltage. FIG. 2 schematically illustrates this powersupply IC as alternating-current voltage source 202. The power supply ICis essentially mounted over one main surface of the mounting board 201but in FIG. 2, the power supply IC is schematically shown asalternating-current voltage source 202 inside the mounting board. Thealternating-current voltage source 202 is coupled to a wiring extendedin a wiring layer internal to the mounting board 201.

The mounting board 201 includes a coil 203. This coil 203 is formedusing, for example, a wiring extended over the one main surface of themounting board 201 or using a wiring extended in an internal wiringlayer when the mounting board has a predetermined number of wiringlayers therein. FIG. 2 illustrates an example in which the mountingboard 201 is a multilayer board having multiple wiring layers therein. Afirst turn of the coil 203 is formed by a wiring extended in one wiringlayer provided in the mounting board 201; and a second turn of the coil203 is formed by a wiring extended in a wiring layer different from theone wiring layer. That is, in this example in FIG. 2, the number ofturns of the coil 203 is two. In cases where the mounting board 201 hasmore than two wiring layers, the number of turns of the coil 203 can befurther increased similarly using the following wirings: wiringsextended in wiring layers respectively different from the wiring layerswhere the wirings for the first and second turns of the coil 203 arelocated. This coil 203 is coupled to the alternating-current voltagesource 202 that outputs alternating-current voltage and hasalternating-current voltage inputted thereto.

In the mounting board 201, there are a hole 215 surrounded with a wiringforming the coil 203 and penetrating the mounting board and a hole 216provided separately from the hole 215 and penetrating the mounting board201. A fixing member, for example, a magnetic material (a representativeexample is an iron core) is passed through these holes 215 and 216 andthis will be described in detail later. Though two holes, the hole 215and the hole 216, are provided in this example, the number of holes maybe one as described later.

Over the one main surface of the mounting board 201, there is provided apackage board 204. The package board 204 is a board for thesemiconductor manufacturer to place a pellet 210, or a semiconductorchip in which a circuit for implementing desired functions is formed.Similarly with the mounting board 201, the package board 204 has apredetermined number of wiring layers therein and in each wiring layer,a wiring formed of metal is extended. The package board 204 in thisembodiment includes a coil 205. This coil 205 is formed by, for example,a wiring extended in a wiring layer provided in the package board 204.Specifically, a first turn of the coil 205 is formed by a wiringextended in one wiring layer provided in the package board 204; and asecond turn of the coil 205 is formed by a wiring extended in a wiringlayer different from the one wiring layer. That is, in this example inFIG. 2, the number of turns of the coil 205 is two. In cases where thepackage board 204 has more than two wiring layers, the number of turnsof the coil 205 can be further increased similarly using the followingwirings: wirings extended in wiring layers respectively different fromthe wiring layers where the wirings for the first and second turns ofthe coil 205 are located.

Over the package board 204, there are provided electrode pads 206 and207. The coil 205 is coupled with the electrode pads 206 and 207. Overthe package board 204, there is provided a semiconductor chip in which acircuit for implementing desired functions is formed, that is, a pellet210. The electrode pads 206 and 207 and the circuit formed in the pellet210 are electrically coupled together through bonding wires 208, 209 andelectrode pads (not shown) formed in the pellet 210. Therefore, the coil205 and the circuit formed in the pellet 210 are electrically coupledtogether. In the above-mentioned example, the coil 205 is electricallycoupled with the circuit included in the pellet 210 through the bondingwires. However, the coupling between the coil 205 and the circuitincluded in the pellet 210 is not limited to this example. When thepellet 210 and the package board 204 are flip-chip bonded together, forexample, the above-mentioned bonding wire 208 is not used. In this case,the circuit included in the pellet 210 is coupled through solder ballsor the like and when these solder balls or the like are bonded with awiring layer provided in the package board 204, the coil 205 and thecircuit included in the pellet 210 are electrically coupled together.

One main surface of the package board 204 where the pellet 210 is formedis covered with a protection member 211 that protects at least thepellet 210. The protection member 211 is composed of, for example,molding resin. In this embodiment, the objects, such as the pellet 210,bonding wire 208, and electrode pads 206 and 207, to be protected formedin the one main surface are protected by this protection member 211. Incases where the protection member 211 is formed of molding resin, theobjects, such as the electrode pads 206 and 207, to be protected formedin the one main surface are sealed with the protection member 211 formedof molding resin.

In the example in FIG. 2, at least the following holes are respectivelypresent in the protection member 211 and the package board 204: a firsthole penetrating the protection member 211 and a second hole surroundedwith a wiring forming the coil 205 and penetrating the package board204. Since FIG. 2 illustrates an embodiment, however, a hole 212 isdepicted as a more detailed concrete example in the drawing. The hole212 is obtained by aligning the first hole and the second hole with eachother and connecting the first and second holes together and penetratesthe protection member 211 and the package board 204. FIG. 2 is depictedon the assumption that there is a hole 213 provided separately from thehole 212 and penetrating the protection member 211 and the package board204. The hole 213 may be divided into a hole penetrating the protectionmember and a hole penetrating the package board. A fixing member, forexample, a magnetic material (a representative example is an iron core)is passed through the holes 212 and 213 and this will be described indetail later. The hole 212 is aligned so that it connects with the hole215 and the hole 212 and the hole 215 together form one hole penetratingthe protection member 211, package board 204, and mounting board 201.This is the same with the hole 213 and the hole 216. In this example inFIG. 2, two holes are provided as the hole 212 and the hole 213;however, the number of holes penetrating the package board 204 and theprotection member 211 may be one as described later.

The semiconductor manufacturer ships a semiconductor package 217including at least the following to a customer as a product: the packageboard including the coil 205; the pellet 210 provided over the packageboard 204 and having a circuit for implementing desired functions formedtherein; the protection member 211 covering the package board 204 andsealing at least the pellet 210; the hole 212 surrounded with a wiringforming the coil 205 and penetrating the protection member 211 and thepackage board 204; and the hole 213 provided separately from the hole212 and penetrating the protection member 211 and the package board 204.This semiconductor package 217 may include another constituent element,for example, a necessary object such as an electrode pad and a bondingwire, needless to add.

The customer, for example, an assembled product manufacturer whopurchased this semiconductor package 217 need mount this semiconductorpackage 217 over the mounting board 201. Consequently, the assembledproduct manufacturer passes a fixing member, specifically, a magneticmaterial for fixing the semiconductor package 217 over the mountingboard 201 through the following: the holes 212 and 213 provided in thepackage board 204 of the purchased semiconductor package 217 and theholes 215 and 216 provided in the mounting board 201. The assembledproduct manufacturer forms this fixing member in a desired shape andfixes, that is, mounts the semiconductor package 217 over the mountingboard 201. When the fixing member is a magnetic material, theconfiguration of the system 200 is preferable in terms of power supplyto the circuit included in the pellet 210 described later. A possibleexample of the fixing member is such a magnetic material 214 in a closedloop as illustrated in FIG. 2. In this case, the magnetic material 214runs from the upper surface of the protection member 211, goes throughthe hole 212 and the hole 215, and is extended to the lower surface ofthe mounting board 201. Thereafter, the magnetic material 214 isextended in the lower surface of the mounting board 201, goes throughthe hole 216 and the hole 213, and reaches the upper surface of theprotection member 211. Further, the magnetic material 214 is extended inthe upper surface of the protection member 211 and reaches the hole 212.As a result, the magnetic material 214 forms a closed loop. When thefixing member is such a magnetic material as a ferrite core, welding byheat is required to form the magnetic material in a closed loop.Therefore, the assembled product manufacturer uses a required apparatusto carrying welding to form the closed-looped magnetic material 214. Themagnetic material as the fixing member for fixing the semiconductorpackage 217 over the mounting board 201 need not be formed in a closedloop. Instead, it may be formed in an open loop in which part of themagnetic material 214 shown in FIG. 2 is discontinuous and interrupted.Also in this case, the semiconductor package 217 can be fixed over themounting board 201 unless the gap portion of the magnetic material in anopen loop is too large. In addition, when this open-looped magneticmaterial is used, necessity for welding by heat is obviated.

When the above-mentioned mounting is completed, the system 200illustrated in FIG. 2 is obtained. However, the configuration of thesystem 200 is not limited to that illustrated in FIG. 2 and includesvarious modifications. FIG. 3 to FIG. 6 schematically explainmodifications to the configuration of the system 200 based on top viewsof the protection member 211 in FIG. 2. To fix the semiconductor package217 over the mounting board 201, at least one hole only has to exist asillustrated in FIG. 3, for example. In this case, the fixing member 214runs from the upper surface of the protection member 211, is extended inthe hole 212 and penetrates the package board 204, and is extended inthe hole 215 and penetrates the mounting board 201. The fixing member214 further goes along the lower surface of the mounting board 201, aside surface of the mounting board 201, a side surface of the packageboard 204, and a side surface of the protection member 211. Then it isextended to the upper surface of the protection member 211. As a result,the fixing member 211 forms a closed loop. In the example in FIG. 3, thefixing member 214 need not be a closed loop and may be an open loop asmentioned above. FIG. 4 is a top view of the protection member 211 inFIG. 2. In addition to the holes 212 and 213, more holes may be providedin the semiconductor package 217. As illustrated in FIG. 5, for example,three holes, that is, the holes 212, 213, 218 may be provided along oneside of the protection member 211. The mounting board 201 is alsoprovided with a hole penetrating the mounting board 201 incorrespondence with the hole 218. As illustrated in FIG. 6, thefollowing measure may be taken: the holes 212 and 213 are provided alongone side of the protection member 211; and the additional hole 218penetrating the protection member 211 and the package board 204 isprovided in proximity to the side opposite the one side. In this case,the semiconductor package 217 is fixed over the mounting board 201 atthree points; therefore, it can be more firmly fixed.

The wiring forming the coil 205 may surround the hole 213 as well as thehole 212. This configuration is effective in increasing the number ofturns of the coil 205. As mentioned above, one turn of the coil 205 isformed in each wiring layer provided in the package board 204. For thisreason, there may be the following cases even when it is desired to makethe number of turns of the coil 205 larger than the number of the wiringlayers provided in the package board 204: the number of turns of thecoil 205 cannot be made larger than the number of the wiring layersprovided in the package board 204 just by ensuring that the wiringforming the coil 205 surrounds only the hole 212.

Consequently, the wiring forming the coil 205 is routed so as tosurround the hole 213. This makes it possible to achieve a number ofturns twice the number of the wiring layers provided in the packageboard 204. To simply increase a number of turns, it is unnecessary toform a wiring so that it surrounds the hole 213. In consideration offlux leakage, described later, that occurs during power supply, however,it is desirable to ensure that the wiring for the coil 205 surrounds thehole 213.

As mentioned above, the semiconductor package 217 can be mounted overthe mounting board 201 without carrying out IR reflow on solder balls.The circuit included in the pellet 210 of the semiconductor package 217does not operate unless sufficient power is supplied to the circuit.Consequently, consideration will be given to the validity of powersupplied to this circuit in this embodiment.

First, alternating-current voltage having a predetermined frequency isapplied from the alternating-current voltage source 202 to the coil 203.Since the current passed through the coil 203 varies with a certainfrequency, the magnetic flux produced by the coil 203 also changes inresponse to change in the current passed through the coil 203. Thevariation in the magnetic flux produced by the coil 203 produces inducedelectromotive force in the coil 205 based on the phenomenon ofelectromagnetic induction. Based on this induced electromotive forceproduced in response to the change in the magnetic flux produced by thecoil 203, an induced current is passed through the coil 205. Thisinduced current flows into the power supply line formed in the pellet210 and the circuit is supplied with power. The circuit formed in thepellet 210 operates based on this power. The magnitude of inducedelectromotive force produced in the coil 205 varies according to thenumber of turns of the coil 203 and the number of turns of the coil 205.To obtain a desired voltage, therefore, the number of turns of the coil203 and the number of turns of the coil 205 only have to be adjusted. Itis unnecessary to provide a step-up circuit or a step-down circuit forconverting voltage values. Since recent circuits formed in the pellet210 operate on direct-current voltage, however, it is required to takethe following measure in actual designing: any of the semiconductorpackages 217 is provided with a rectification circuit.

The induced electromotive force produced in the coil 205 is alsoinfluenced by the amount of flux leakage that does not interlink withthe coil 205 in the magnetic flux produced by the coil 203. When thecoil 203 and the coil 205 are ideally coupled together and the couplingcoefficient is 1, flux leakage does not occur. Since in reality, thiscoupling coefficient cannot be 1, however, it is required to takereduction in induced electromotive force due to flux leakage as wellinto account in real designing. This is because when the inducedelectromotive force is reduced, power that can be supplied to the pellet210 is also reduced. Consequently, the measure illustrated in FIG. 2 aswell is taken to reduce the amount of flux leakage as much as possible.That is, the magnetic material 214, for example, an iron core, adoptedas the fixing member is passed through the hole 212 and the hole 213.The magnetic material 214 assumes a role of a fixing member that fixesand mounts the semiconductor package 217 over the mounting board 201. Inaddition, it also assumes a role of reducing the amount of flux leakagein the magnetic flux produced from the coil 204 to ensure the certainmagnitude of induced electromotive force of the coil 205.

Even though the magnetic material 214 is passed as mentioned above, fluxleakage is also caused by the following: a gap produced between themagnetic material 214 and the coil 203 and a gap produced between themagnetic material 214 and the coil 205. In reality, therefore, the lossof induced electromotive force is inevitable even with the magneticmaterial 214 provided. However, the loss of induced electromotive forcecan be largely suppressed by using a magnetic material 214, for example,a ferrite core sufficiently high in magnetic permeability to fix thesemiconductor package 217 over the mounting board 201. This is becausemost of the magnetic flux produced by the coil 203 goes through themagnetic material 214 and interlinks with the coil 205. In this case, itis possible to disregard a gap between the coil 203 and the magneticmaterial 214 and a gap between the coil 205 and the magnetic material214.

Even though the above contrivance is made in an attempt to suppressreduction in induced electromotive force and ensure power that can besupplied to the pellet 210, the following takes place when the system200 is actually designed: power that can be transmitted to the pellet210 is lost by the impedance of the coil 205 itself. In reality, asmentioned above, it is required to provide a semiconductor package 217with a rectification circuit; therefore, it is required to also take theloss of power due to this rectification circuit into account. Further,power may be lost by eddy current depending on the shape of the coil205. The hysteresis loss of this power must also be taken into account.

In consideration of the foregoing, it is appropriate to suppose thatseveral tens of percent of power inputted to the coil 203 in themounting board 201 is lost in real designing.

Meanwhile, recent circuits formed in the pellet 210 operate based on adirect-current voltage of 1 V or so supplied to the power supply lineprovided in the pellet 210. Even though power based on the voltageoutputted by the alternating-current voltage source 202 is lost severaltens of percent or so before it is supplied to the circuit included inthe pellet 210, it is supposed that: a direct-current voltage of 1 V orso can be sufficiently supplied to the power supply line provided in thepellet 210 by setting the peak-to-peak value of alternating-currentvoltage supplied by the alternating-current voltage source 202 to 2 V orso.

The foregoing is a restriction imposed on the following when the coil203 and the coil 205 are configured as a transformer and power issupplied from the mounting board 201 to the circuit formed in the pellet210: the value of voltage supplied by the alternating-current voltagesource 202 taken into account when the system 200 is actually designed.Even though the restriction on the voltage value is met, however, astructural restriction must also be met to actually implement the system200. In the system 20 in FIG. 2, it is of a problem whether or not thestructure of the coil 203, coil 205, and magnetic material 214 isrealistic in supplying power to the pellet 210. (This is because whenthe cross-sectional area of the magnetic material is realistic, thecross-sectional area of a hole through which the magnetic material 214is passed is also realistic.)

Consequently, consideration will be given to structural restrictions onthe coil 203, coil 205, and magnetic material 214. A structuralrestriction on the coil 203 and the coil 205 is their number of turnsrequired to supply required power to the circuit formed in the pellet210. The reason for this is as follows. When the magnetic material 217,for example, a ferrite core sufficiently high in magnetic permeabilityis used to fix the semiconductor package 214 over the mounting board201, the following takes place: the magnetic flux produced by the coil203 is almost all passed through the magnetic material 214 andinterlinks with the coil 205. Therefore, a gap between the coil 203 andthe magnetic material 214 and a gap between the coil 205 and themagnetic material 214 can be disregarded. Thus, when a number of turnsis too large as compared with the number of wiring layers provided inthe mounting board 201 or the package board 204, the following takesplace: even when the alternating-current voltage source 202 outputsalternating-current voltage whose peak-to-peak value is 2V, sufficientpower cannot be supplied to the circuit included in the pellet 210 withthe coil 203 or coil 205 formed using a wiring extended in the wiringlayer. This is because in consideration of that the system 200 isactually mounted over a small produce, it is not realistic to take thefollowing measure: the number of the wiring layers in the package board204 or the mounting board 201 is increased to make the package board 204or the mounting board 201 too thick.

A possible structural restriction on the magnetic material 214 is thecross-sectional area and length of the magnetic material 214. Theinduced electromotive force produced in the coil 205 is based on changein magnetic flux interlinked with the coil 205. Mathematically, it isbased on the amount of change per unit time in the density of magneticflux interlinked with the coil 205 as according to Faraday's law. Asmentioned above, the magnetic flux produced by the coil 203substantially goes through the magnetic material 214 and interlinks withthe coil 205. In consideration of these, the cross-sectional area of themagnetic material 214 relates to magnetic flux density and is thusimportant. With respect to the length of the magnetic material 214,meanwhile, it can be supposed from the above viewpoint that it only hasto be the extent that the semiconductor package 217 can be fixed overthe mounting board 201.

So, it turns out that consideration must be given to the numbers ofturns of the coil 203 and the coil 205 and the cross-sectional area ofthe magnetic material 214. It is known from an analysis of a transformerthat the maximum density Bm of magnetic flux that can be passed throughthe magnetic material 214, for example, an iron core isBm=V/(√2π*f*S*N), where π is circumference ratio; f is the frequency ofalternating-current voltage; S is the cross-sectional area of themagnetic material 214, for example, an iron core; and N is the number ofturns of a coil wound around the iron core (for example, the number ofturns of each of the coil 203 and the coil 205 when the coil 203 and thecoil 205 are identical in number of turns). Here, 3.14 will be taken asthe circumference ratio π and 2V, which is the peak-to-peak value ofvoltage outputted by the alternating-current voltage source 202, will besubstituted for V. 2 GHz=2*10⁹, which is a typical frequency at whichthe oscillation of voltage is actually achieved, will be substituted forthe frequency f of alternating-current voltage.

The rest is the cross-sectional area of the magnetic material 214 andthe maximum magnetic flux density Bm. When these values are determined,the number of turns N of each of the coil 203 and the coil 205 isdetermined from the above expression. This N refers to the number ofturns N obtained when the maximum magnetic flux density is passedthrough the magnetic material 214 and this means that a number of turnsnot less than N is required. As an example, it will be assumed that aferrite core is used as the magnetic material 214. In this case, Bm is0.5 T or so and 0.5 is substituted for Bm. On the assumption that thecross section of the iron core is, for example, a square measuring 1 mmper side, 1.0*10⁻⁶ square meters is adopted for the cross-sectional areaof the iron core. In this case, the cross section of the iron core issufficiently smaller than the area of the upper surface or lower surfaceof the protection member 211 or package board 204 of the semiconductorpackage 217. Therefore, the opening area of the hole 212, hole 213, hole215, or hole 216 does not become larger than necessary. In thesemiconductor package 217 illustrated in FIG. 2, specifically, forexample, the thickness of the protection member 211 is 200 μm and thelength of longitudinal sides and the length of horizontal sides are each10 mm or so. Naturally, this is also the case with the package board204.

Therefore, in an example in which the cross-sectional area of the ironcore is 1.0*10⁻⁶ square meters, the structure of the actual system 200is not unrealistically restricted even with the size of the protectionmember 211 or the package board 204 taken into account.

Using the numeric values in the above example, the minimum number ofturns N required for the coil 203 and the coil 205 to implement thefollowing will be determined: the circuit formed in the pellet 210 isoperated by supplying alternating-current voltage whose peak-to-peakvalue is 2V from the alternating-current voltage source 202.

When the number of turns N is actually calculated,N>V/(√2*π*f*S*Bm)=2/(4.44*2*10⁹*1*10⁻⁶*0.5)=0.45*10⁻³. That is, thenumber of turns only has to be 1 at least. Therefore, it is supposedthat a larger-than-necessary number of turns is not necessary for thecoil 203 or the coil 205.

It is understood from the foregoing that the system 200 in thisembodiment has an appropriate structural size in terms of real designand is realistic in terms of technology. According to this embodiment,therefore, it is possible to adopt a structure that enables thepractical manufacture of products and mount the semiconductor package217 over the mounting board 201 without carrying out IR reflow on solderballs. Further, it is possible to supply sufficient power to the circuitincluded in the pellet 210 of the semiconductor package 217 to operatethe circuit.

Description will be given to a manufacturing method for this system 200.The wiring pattern of wirings extended in the wiring layers provided inthe package board 204 is designed so that the coil 205 is formed in adesired position in the package board 204 of the semiconductor package217. Then the package board 204 with this coil 205 formed therein isprepared. Required constituent elements, such as the pellet 210, areformed thereover using publicly known manufacturing techniques and thepellet 210 and the like are sealed with the protection member 211.Subsequently, the hole 212 penetrating the protection member 211 and thepackage board 204 is formed by drilling so that it is surrounded withthe wiring forming the coil 205 based on the position where the coil 205is formed. At the same time, the hole 213 is formed by drilling so thatit penetrates the protection member 211 and the package board 204. As aresult, the semiconductor package 217 is manufactured. As mentionedabove, the semiconductor manufacturer ships the thus formedsemiconductor packages 217 to the customer. The customer designs thewiring pattern of wirings extended in the wiring layers provided in themounting board 201 so that the coil 203 is also formed in the mountingboard 201. Then the customer prepares a mounting board with the coil 203formed therein. The hole 215 penetrating the mounting board 201 isformed by drilling so that it is surrounded with the wiring forming thecoil 203 based on the position where the coil 203 is formed. At the sametime, the hole 216 is formed by drilling so that it penetrates themounting board 201. Thereafter, the customer aligns each semiconductorpackage and mounts each semiconductor package 217 over the mountingboard 201 by the above-mentioned technique and the system 200 is therebyformed.

Second Embodiment

Description will be given to the second embodiment. FIG. 7 illustrates asystem 700 in the second embodiment of the invention disclosed in thisspecification. It is different from the first embodiment in that:multiple semiconductor packages, that is, a first semiconductor package718 and a second semiconductor package 719 are stacked over a mountingboard 701; the second semiconductor package 719 has an antenna 717 andthough not shown in the drawing, the first semiconductor package alsohas the same antenna as the antenna 717. Hereafter, concrete descriptionwill be given to the configuration of the system 700. Portionsoverlapping with the content of the description of the first embodimentwill be omitted as appropriate.

As in the first embodiment, the mounting board 701 is provided with acoil 703, which is supplied with alternating-current voltage from analternating-current voltage source 702. As in the first embodiment,further, holes 711 and 712 are formed.

Over the mounting board 701, the first semiconductor package 718 isformed. The first semiconductor package 718 includes a package board704. This package board 704 has a coil 705 formed therein as in thefirst embodiment and though not shown in the drawing, a pellet thatoperates with power supplied is also provided over the package board.Though not shown in the drawing, constituent elements, such as a bondingwire, required for electrical coupling between the pellet and the coil705 are also provided in the package board 704. Unlike the firstembodiment, however, the same antenna as the above-mentioned antenna 717is provided over the package board 704 and this antenna is coupled tothe circuit included in the pellet formed in the package board 704. Thisantenna wirelessly radiates and transmits signals from the pellet andoutputs received signals to the circuit included in the pellet. Thisantenna is, for example, a planar spiral antenna formed of a wiringextended over the package board 704. A protection member 706 sealing thepellet and the antenna is provided over the package board 704. As in thefirst embodiment, holes 713 and 714 are formed and the holes 713 and 714connect with the holes 711 and 712 as the result of alignment;therefore, holes penetrating the protection member 706, package board704, and mounting board 701 are formed. As in the first embodiment 1,the hole 713 is divided into a first hole penetrating the protectionmember and a second hole surrounded with a wiring forming the coil 705and penetrating the package board 704. Similarly, the hole 714 is alsodivided into two holes.

Over the protection member 706 included in the first semiconductorpackage 718, the package board 707 included in the second semiconductorpackage 719 is provided. The package board 707 is also provided with acoil 708 similarly with the package board 704 of the first semiconductorpackage 718. This coil 708 is coupled to a pellet 710 provided over thepackage board 707. As a result, the circuit formed in the pellet 710 andthe coil 708 are electrically coupled together. Unlike the firstembodiment, the antenna 717 is provided over the package board 707. Thisantenna 717 is coupled to the circuit included in the pellet 710 formedin the package board 707. This antenna 717 wirelessly radiates andtransmits signals form the pellet 710 and outputs received signals tothe circuit included in the pellet 710. This antenna 717 is, forexample, a planar spiral antenna formed of a wiring extended over thepackage board 707. A protection member 709 sealing the pellet 710 andthe antenna 717 is provided over the package board 707. As in the firstembodiment, holes 715 and 716 are formed and the holes 715 and 716connect with the holes 713 and 714 by alignment. As a result, the holes715 and 716 also connect with the holes 711 and 712 in the mountingboard 701. Therefore, one can argue that holes penetrating theprotection member 709, package board 707, protection member 706, packageboard 704, and mounting board 701 are formed. As in the firstembodiment, the hole 715 is divided into two holes, a hole penetratingthe protection member 709 and a hole surrounded with a wiring formingthe coil 708 and penetrating the package board 707. The hole 716 is alsodivided into a hole penetrating the protection member 709 and a holepenetrating the package board 707.

As in the first embodiment, a fixing member, for example, a magneticmaterial 720 is passed through the holes 711 and 712, 713 and 714, and715 and 716; and the first semiconductor package 718 and the secondsemiconductor package 719 are mounted over the mounting board 701. Whena magnetic material is adopted as the fixing member, the magneticmaterial 720 is, for example, a ferrite core as in the first embodiment.

In the second embodiment, the first semiconductor package 718 and thesecond semiconductor package 719 are used to implement the system 700.For this reason, it is required to electrically couple together thecircuit included in the pellet of the first semiconductor package 718and the circuit included in the pellet 710 of the second semiconductorpackage 719. This is because: when this electrical coupling is achieved,electrical signals can be communicated between the circuit included inthe pellet of the first semiconductor package 718 and the circuitincluded in the pellet 710 of the second semiconductor package 719; andthus a system for achieving desired functions is built.

In the second embodiment, consequently, the circuit included in thepellet of the first semiconductor package 718 and the circuit includedin the pellet 710 of the second semiconductor package 719 areelectrically coupled together by taking the following measure: theantenna provided in the first semiconductor package 718 and the antenna717 provided in the second semiconductor package are caused towirelessly communicate with each other. More specific description willbe given. The antenna provided in the first semiconductor package 718radiates signals from the circuit included in the pellet provided in thefirst semiconductor package 718 and transmits them to the antenna 717 ofthe second semiconductor package 719. The antenna 717 receives signalsfrom the antenna provided in the first semiconductor package 718 andoutputs the received signals to the circuit included in the pellet 710.

Similarly, the antenna 717 receives and radiates signals from thecircuit included in the pellet 710 and outputs them to the antennaprovided in the first semiconductor package 718. The antenna outputs thesignals received from the antenna 717 to the circuit included in thepellet provided in the first semiconductor package 718.

Thus signals are communicated between the first semiconductor package718 and the second semiconductor package 719. Since signals arewirelessly communicated between the antennas, it is required that thesignals outputted from these antennas should have a frequency with whichwireless communication is enabled. For example, the signals are requiredto have a frequency of 2 GHz or so, which is used in wireless LAN,Bluetooth, and the like. Non-patent Document 2 mentioned above describesthat spiral antennas 240 μm square can carry out wireless communicationwithin a range of up to 120 μm using a frequency of 1.2 GHz or so.Consequently, consideration will be given to the following based on thethickness of each member forming recent semiconductor packages: the sizeof each of the antenna 717 in the system 700 illustrated in FIG. 7 andthe antenna included in the first semiconductor package 718.

In FIG. 7, the thickness of each of the package board 704 and thepackage board 707 is, for example, 300 μm. The thickness of each of thepellet included in the first semiconductor package 718 and the pellet710 included in the second semiconductor package 719 is 120 μm. Thethickness of each of the protection member 706 and the protection member709 is 200 μm. The antenna included in the first semiconductor package718 is formed over the package board 704 and the antenna 717 included inthe second semiconductor package 719 is formed over the package board707. Thus the distance between these antennas is shortest when they arevertically opposed to each other and the shortest distance is 500 μm,which is the sum of the thickness of the protection member 706 and thethickness of the package board 707. As mentioned above, Non-patentDocument 1 discloses that spiral antennas 240 μm square can carry outwireless communication within a range of up to 120 μm using a frequencyof 1.2 GHz or so. In consideration of this, wireless communication canbe carried out when each of the antenna included in the firstsemiconductor package 718 and the antenna 717 included in the secondsemiconductor package 719 is a spiral antenna approximately 1000 μmsquare.

When these antennas are not so arranged that they are vertically opposedto each other, the distance between the antennas is increased and thusit is required to increase the size of each antenna. As described inrelation to the first embodiment, however, the package boards 704, 707and the protection members 706, 709 are each 10 mm in longitudinallength and in horizontal length. Therefore, it is supposed that increasein the size of the spiral antenna provided in each semiconductor packagecan be sufficiently coped with. Therefore, one can argue that thisembodiment can be technically implemented.

FIG. 7 illustrates an example in which the two semiconductor packagesare stacked and mounted over the mounting board 701. However, the numberof the semiconductor packages stacked over the mounting board 701 may begreater than two. For example, a third semiconductor package may beadditionally stacked over the second semiconductor package 719 in FIG.7. In this case, a flat spiral antenna is also provided over the packageboard of the third semiconductor package. The antenna included in thethird semiconductor package wirelessly communicates with the antennaincluded in the first semiconductor package 718 and the antenna 717included in the second semiconductor package 719. However, when theantenna included in the third semiconductor package and the antennaincluded in the first semiconductor package are caused to wirelesslycommunicate with each other, the distance between the two antennas isincreased. For this reason, there is a possibility that direct wirelesscommunication cannot be carried out between the two antennas dependingof the size of these antennas. In this case, for example, the followingmeasure can be taken: signals are once transmitted to the antenna 717included in the second semiconductor package 719 and their intensity isamplified at the amplifier circuit provided in the second semiconductorpackage 719; and then the signals are transmitted from the antennaprovided in the second semiconductor package 719 to the antenna includedin the first semiconductor package 718.

Third Embodiment

FIG. 8 illustrates the configuration of a system 800 in the thirdembodiment. Hereafter, the description of constituent elementsoverlapping with the above description will be omitted. FIG. 8 is a topview of the system 800. In the example in FIG. 8, multiple semiconductorpackages are mounted over a mounting board 801. In this top view, therespective semiconductor packages are indicated by a protection member802, a protection member 806, and a protection member 810. In the thirdembodiment, as seen from FIG. 8, the multiple semiconductor packages aremounted over the plane of one main surface of the mounting board 801unlike the second embodiment. Similarly with the protection member 709in the second embodiment, the protection member 802 protects a pelletand the like provided over a package board though they are not shown inthe drawing. A hole 803 and a hole 804 are formed in the upper surfaceof the protection member 802 and penetrate the protection member 802 andthe package board, not shown. In the mounting board 801, holespenetrating the mounting board 801 are provided in positionscorresponding to the hole 803 and the hole 804. The semiconductorpackage including the protection member 802 is fixed over the mountingboard 801 by a fixing member 805 passed through these holes.

Similarly with the protection member 709 in the second embodiment, theprotection member 806 also protects a pellet and the like provided overa package board though they are not shown in the drawing. In the examplein FIG. 8, therefore, a hole 808 and a hole 809 are formed in the uppersurface of the protection member 806 and penetrate the protection member806 and the package board, not shown. In the mounting board 801, holespenetrating the mounting board 801 are provided in positionscorresponding to the hole 808 and the hole 809. The semiconductorpackage including the protection member 806 is fixed over the mountingboard 801 by a fixing member 807 passed through these holes.

In the package boards corresponding to the protection member 802 and theprotection member 806, antennas different in shape from those in thesecond embodiment are provided. More specific description will be given.In the third embodiment, such antennas 901 and 902 as illustrated inFIG. 9 are provided. In FIG. 9, the holes 808, 809 of the semiconductorpackage including the protection member 806 and the fixing member 807are omitted. In actuality, however, the semiconductor package includingthe protection member 806 has the holes 808 and 809 formed therein andis provided with the fixing member 807 as illustrated in FIG. 8. In thiscase, similarly with the embodiments described up to this point, thesemiconductor package including the protection member 806 is provided inits package board with a coil. This coil is so provided that itsurrounds the fixing member 807 passed through the hole 808 and the hole809. Also in the mounting board, there is provided a separate coilcoupled with a power supply IC and the fixing member 807 is surroundedwith this separate coil provided in the mounting board. Similarly withthe embodiments described up to this point, power is supplied to thecircuit included in the pellet of the semiconductor package includingthe protection member 806. The power is supplied through the coilprovided in the package board of the semiconductor package including theprotection member 806. With respect to the fixing members, the fixingmember 805 may form a closed loop or an open loop integrally with thefixing member 807. This makes it unnecessary to provide a separate coilcoupled with the power supply IC in the mounting board.

In the example in FIG. 9, the semiconductor package including theprotection member 802 has the antenna 901. The semiconductor packageincluding the protection member 806 has the antenna 902. In the secondembodiment, the antennas for electrically coupling the respectivesemiconductor packages are formed as flat spiral antenna over thepackage boards included in the respective semiconductor packages. In thethird embodiment, meanwhile, the individual semiconductor packages aremounted over the plane of the mounting board 801; therefore, the shapeof each antenna is different from that in the second embodiment. Morespecific description will be given. It is required to communicatesignals between the semiconductor package including the protectionmember 802 and the semiconductor package including the protection member806. Therefore, the spiral shape of the antenna 901 and the spiral shapeof the antenna 902 are opposed to each other. For this reason, each ofthe antennas 901, 902 is not formed only of a wiring extended over thepackage board included in the relevant semiconductor package. They areformed also using wirings extended in wiring layers in the packageboards included in the respective semiconductor packages. When theantenna 901 and the antenna 902 are formed as mentioned above, it ispossible to effectively increase the range within which communicationcan be carried out between antennas and wireless communication betweenthe antennas 901 and 902 is enabled. Therefore, it is possible tocommunicate signals between the semiconductor package including theprotection member 802 and the semiconductor package including theprotection member 806. The invention disclosed in this specification canbe hence implemented even when the two semiconductor packages aremounted over the plane of the one main surface of the mounting board801.

With reference to FIG. 8 again, the semiconductor package mounted overthe mounting board 801 and including the protection member 810 is notprovided with a hole or a fixing member. This is based on the assumptionthat the semiconductor package including the protection member 810 is asemiconductor package equivalent to a conventional technology in whichthe invention disclosed in this specification is not implemented. Oneexample of possible cases is that the semiconductor package includingthe protection member 810 is a semiconductor package from a competitorto which the invention disclosed in this specification is not applied.To operate the system 800, even in this case, it is required tocommunicate signals between the semiconductor package including theprotection member 802 and the semiconductor package including theprotection member 810. This is because the system 800 is operated whenthe circuits respectively included in the semiconductor packages mountedover the mounting board 801 communicate signals therebetween.

The semiconductor package including the protection member 810 is mountedover the mounting board 801 using solder balls as illustrated in FIG. 1.Thus the technique illustrated in FIG. 9 cannot be adopted forimplementing the following: the semiconductor package including theprotection member 802 and the semiconductor package including theprotection member 806 are wirelessly electrically coupled together usingthe antenna 901 and the antenna 902.

In this case, consequently, the following measure can be taken: signalsoutputted by the semiconductor package including the protection member802 using the antenna are received by a spiral antenna provided in themounting board 801; and these received signals are transmitted to thesemiconductor package including the protection member 810 by a route byway of a solder ball. More specific description will be given. Thoughnot shown in the drawing, the mounting board 801 is provided with thespiral antenna in such a shape as that of the coil 703 in FIG. 7. Overthe package board of the semiconductor package including the protectionmember 802, there is provided a spiral antenna in such a shape as thatof the antenna 717 in FIG. 7. The spiral shape of this spiral antennaprovided in the mounting board 801 and the spiral shape of this spiralantenna provided in the semiconductor package including protectionmember 802 like the antenna 717 in FIG. 7 are opposed to each other.This configuration makes it possible to transmit signals outputted bythe semiconductor package including the protection member 802 to thesemiconductor package including the protection member 810 after they arereceived at the mounting board 801.

This is the same with the electrical coupling between the semiconductorpackage including the protection member 806 and the semiconductorpackage including the protection member 810. However, it is unnecessaryto purposely separately provide the mounting board 801 with a spiralantenna corresponding to the semiconductor package including theprotection member 806 in the following cases: cases where the antennaprovided in the mounting board 801 and receiving signals from thesemiconductor package including the protection member 802 and thesemiconductor package including the protection member 806 cancommunicate with each other in terms of distance.

Up to this point, description has been given to embodiments of theinvention. However, other modifications those skilled in the art canconceive are also included in these embodiments. The scope of right ofthe invention is determined by “What is claimed is” and should not beconstrued as limited to the description of the embodiments.

1. A semiconductor package comprising: a package board including a coilfor supplying power based on an induced current passed in response tochange in magnetic flux; a pellet provided over the package board andincluding a circuit operating based on power supplied from the coil; aprotection member covering the package board and protecting at least thepellet; a first hole penetrating the protection member; and a secondhole surrounded with a wiring forming the coil and penetrating thepackage board.
 2. The semiconductor package according to claim 1,wherein the first and second holes are holes for passing therein afixing member for fixing the semiconductor package over a mountingboard.
 3. The semiconductor package according to claim 2, furthercomprising: an antenna electrically coupled with the circuit included inthe pellet and capable of transmitting and receiving signals.
 4. Thesemiconductor package according to claim 2, wherein the coil is formedof a wiring extended in a wiring layer formed between the upper surfaceopposite the pellet among the surfaces of the package board and thelower surface opposed to the upper surface.
 5. The semiconductor packageaccording to claim 4, wherein the wiring layer is comprised of aplurality of layers, the wiring of the first turn of the coil isextended in one layer included in the wiring layer, and the wiring ofthe second turn of the coil is extended in a layer different from theone layer.
 6. The semiconductor package according to claim 3, in whichthe coil, the package board, the pellet, the protection member, and theantenna are respectively a first coil, a first package board, a firstpellet, a first protection member, and a first antenna, furthercomprising: a second package board provided over the first protectionmember and including a second coil for supplying power based on aninduced current passed in response to change in magnetic flux; a secondpellet provided over the second package board and including a circuitoperating based on power supplied from the second coil; a secondprotection member covering the second package board and protecting atleast the second pellet; a third hole penetrating the second protectionmember; a fourth hole surrounded with a wiring forming the second coiland penetrating the second package board; and a second antennaelectrically coupled with the circuit included in the second pellet andcapable of transmitting and receiving signals.
 7. The semiconductorpackage according to claim 6, wherein signals are transmitted andreceived between the first antenna and the second antenna.
 8. Thesemiconductor package according to claim 7, wherein each of the firstantenna and the second antenna is a spiral antenna and the respectivespiral shapes thereof are opposed to each other.
 9. The semiconductorpackage according to claim 6, wherein the third and fourth holes areholes for passing a fixing member for fixing the semiconductor packageover a mounting board.
 10. The semiconductor package according to claim1, further comprising: a fifth hole provided separately from the firsthole and penetrating the protection member; and a sixth hole providedseparately from the second hole and penetrating the package board,wherein the sixth hole is surrounded with a wiring forming the coil. 11.The semiconductor package according to claim 1, wherein the inducedcurrent passed through the coil is based on change in magnetic fluxproduced from a coil formed in a mounting board for mounting thesemiconductor package.
 12. The semiconductor package according to claim2, wherein the fixing member is a magnetic material.
 13. A systemcomprising: a mounting board including a first coil supplied withvoltage; a package board provided over the mounting board and includinga second coil for supplying power based on an induced current passed inresponse to change in magnetic flux based on variation in the voltage; apellet provided over the package board and including a circuit operatingbased on power supplied from the second coil; a protection membercovering the package board and protecting at least the pellet; a firsthole penetrating the protection member; a second hole surrounded with awiring forming the second coil and penetrating the package board; athird hole surrounded with a wiring forming the first coil andpenetrating the mounting board; and a fixing member running through theinterior of each of the first to third holes and fixing the packageboard and the protection member over the mounting board.
 14. The systemaccording to claim 13, further comprising: an antenna electricallycoupled with the circuit included in the pellet and capable oftransmitting and receiving signals.
 15. The system according to claim13, wherein the fixing member is a magnetic material in a closed loopshape or an open loop running through the interior of each of the firstto third holes.
 16. The system according to claim 13, in which thepackage board, the pellet, the protection member, the fixing member, andthe antenna are respectively a first package board, a first pellet, afirst protection member, a first fixing member, and a first antenna,further comprising: a second package board provided over the plane wherethe first package board is provided among the planes included in themounting board and including a third coil for supplying power based onan induced current passed in response to change in magnetic flux basedon variation in the voltage; a second pellet provided over the secondpackage board and including a circuit operating based on power suppliedfrom the third coil; a second antenna provided in the second packageboard, electrically coupled with the circuit included in the secondpellet, and capable of transmitting and receiving signals; a secondprotection member covering the second package board and protecting atleast the second pellet; a fourth hole penetrating the second protectionmember; a fifth hole surrounded with a wiring forming the third coil andpenetrating the second package board; a sixth hole penetrating themounting board; and a second fixing member running through the interiorof each of the fourth to sixth holes and fixing the second package boardand the second protection member over the mounting board.
 17. The systemaccording to claim 16, wherein the second fixing member is surroundedwith a wiring forming the first coil and forms an open loop or a closedloop integrally with the first fixing member.
 18. The system accordingto claim 16, further comprising: a fourth coil included in the mountingboard and supplied with the voltage, wherein the second fixing member issurrounded with a wiring forming the fourth coil.